[meteorite-list] Spirit Finishes Mountain Marathon

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed Aug 24 12:32:49 2005
Message-ID: <200508241555.j7OFtNF29991_at_zagami.jpl.nasa.gov>

http://www.nature.com/news/2005/050822/full/050822-3.html

Spirit finishes mountain marathon

Resilient martian rover takes in the view.

Mark Peplow
nature.com
23 August 2005

After a long uphill hike, there's no better reward than the view from
the summit. So it is understandable that the operators behind the Mars
rover Spirit had their robot pause to survey the terrain after it
reached the top of Husband Hill, even if the area does look remarkably
similar to the area from which the rover just came.

"It's a beautiful view," says Ray Arvidson, a geologist from Washington
University in St Louis, Missouri, and second-in-command of the rover
science team.

"It's one of the best pictures Spirit has taken," he adds, because it
contains a little bit of everything his team has been looking for on
Mars. In the distance, a dust devil dances across the plain, and ridges
of windblown sand lap at the rover's wheels. Nearby, rocks crusted with
mineral grains carry clues to Mars's geological history.

Milking a long life

Perhaps more surprising than the view is the simple fact that Spirit
made it to the top of the highest peak in the Columbia Hills formation.

Spirit has been exploring the red planet for 582 martian days, or sols,
and the rover just keeps on keeping on. This epic climb has taken more
than a year, and the robot shows no signs of flagging.

Although its right front wheel is a little sticky, and the grinding tool
has been completely worn down by too many hard, volcanic rocks,
"everything seems to be working OK", says Arvidson.

Remote control

Initially slated to last just 90 days each on Mars, Spirit and its twin
rover Opportunity have completed more than a thousand days of work
between them. The mission's homepage now logs the rovers' progress in
terms of 'sols past warranty'.

The mission scientists spent the first nine months of the project at the
Jet Propulsion Laboratory in Pasadena, California. But as the rovers
refused to die, the scientists returned to their home universities in
September 2004 to continue the campaign remotely.

Arvidson has telephone meetings with his colleagues every day to plan
the rovers' activities. But the resilience may be a mixed blessing:
"We've given up Saturdays and Sundays for the most part," he says.

Unflagging spirit

Spirit has driven about 5 kilometres since it touched down in Gusev
Crater on 4 January 2004. For much of its mission it has been
overshadowed by its twin Opportunity, which has found copious evidence
of minerals shaped by water on the other side of the planet.

But since beginning its climb into the Columbia Hills in June 2004,
Spirit has found a much wider variety of rocks. Some contain minerals
that probably formed in water, although "none of it shouts out that it
was formed in a lake", says Arvidson.

Spirit will spend several weeks at the summit to measure how much the
Sun's rays heat the slopes of distant hills, and how this drives Mars's
windy weather. "We're at this hilltop observatory now, so we can make
some unique measurements," Arvidson explains.

The rover is getting in position to take a full colour, 360? panorama
photograph on 25 August, which should pick out other peaks in the
Columbia Hills, along with the valleys and plains on either side. But
what the scientists are most keen to get are the close-ups of rock and
soil on the far side of the hill, rather than the long views.

Giving up the ghost

Once Spirit has picked its way down the southern flank of the hill, it
will try to reach Home Plate, an area of layered rock more than a
kilometre away.

No one knows how much longer the rovers will last. Although they show no
signs of flagging, they could give up at any moment. Some flexible
electrical cables, for example, may eventually snap.

But the solar panels are doing better than predicted at providing power,
in part thanks to the dust devils, which give the robots a spring clean
and blow dirt off the panels.

And until they do give up, the scientists will stay with them. "It's
like a year and a half of adrenaline," laughs Arvidson. "And we find
something new every sol."
Received on Wed 24 Aug 2005 11:55:21 AM PDT